It is known in the art of aircraft engine control to use various computerized systems to aid in navigation, flight control and engine management. These systems may include, for example, various warning systems, ground proximity systems, engine control systems, and aircraft control systems, just to name a few. Warning systems help the aircraft to continue to operate under safe conditions or to avoid entering an unsafe operating condition or avoid ground obstacles. Ground proximity systems may warn of approaching obstacles or automatically adjust autopilot settings to avoid them. Engine control systems may adjust fuel flow and other operating conditions in response to changes in air pressure and other variables. Aircraft control systems may inhibit certain maneuvers that might result in undesired operation. Engine control systems may adjust engine operation in the highly unlikely event of an engine failure in a multi-engine aircraft.
While each of the above-mentioned systems is useful, they may not adequately deal with other conditions that can adversely affect operation of an aircraft. Of particular concern is control of the engines when the aircraft drifts out of its normal operating envelope, in particular when approaching ground obstacles that may place it below a predetermined altitude threshold and an engine out-of-range condition occurs, especially a condition that would prompt the engine control system to automatically decrease an engine throttle setting to avoid engine damage. Thus, there continues to be a need for improved engine control systems coupled with a ground proximity system that adjusts the engine operating envelope to preclude an engine control system from aggravating a prospective or actual departure from safe altitude operation. In addition, it is desirable that the ground proximity system and engine control system interact automatically without requiring pilot observation or intervention. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.